1. Field of the Invention
The present invention relates to a method of preparing a ruminant feed material with decreased rumen digestibility. The present invention also relates to a ruminant feed material with decreased rumen digestibility.
2. Description of the Related Art
The diet of ruminant animals typically includes feedstuffs that contain protein. An adequate amount of protein should be delivered to a ruminant animal to ensure the optimal development of the meat and milk provided thereby. However, some of the protein ingested by the ruminant animal typically becomes degraded in the rumen. For example, an amount of the ingested protein typically is converted to ammonia in the rumen. The amount of protein thus delivered to the small intestine of the ruminant animal typically is less than the total amount of protein ingested, as a significant amount of protein can be lost in the rumen. Therefore, it is beneficial to increase the resistance of the protein to rumen degradation in order to maximize the amount of the ingested protein flowing to the small intestine of the ruminant animal.
In light of the importance of delivering an adequate amount of protein to ruminant animals, methods have been proposed for estimating the rumen degradation resistance of the protein present in ruminant feedstuffs. For example, measuring the amount of ammonia in the rumen can provide a qualitative determination of the resistance of the protein to rumen degradation.
In addition, the rumen degradation resistance of a protein can be qualitatively determined by measuring the nitrogen solubility of the protein. See, e.g., B. A. Crooker et al., xe2x80x9cSolvents for Soluble Nitrogen Measurements in Feedstuffsxe2x80x9d, Journal of Dairy Science, Vol. 61, pp. 437-47 (1977). In this regard, the nitrogen solubility of a particular protein is generally a good indicator of the rumen degradability of the protein. That is, a protein feedstuff having a lower nitrogen solubility generally has a greater resistance to rumen degradation. Thus, decreasing the nitrogen solubility of a protein feedstuff fed to a ruminant animal typically increases the intake of protein by the ruminant animal.
Various documents discuss the significance of the nitrogen solubility of protein present in ruminant animal feedstuffs. See, e.g., Glimp et al., xe2x80x9cEffect of Reducing Soybean Protein Solubility by Dry Heat on the Protein Utilization of Young Lambsxe2x80x9d, Journal of Animal Science, Vol. 26, pp. 858-61 (1967); Chalmers et al., xe2x80x9cRuminal Ammonia Formation in Relation to the Protein Requirement of Sheepxe2x80x9d, Journal of Agricultural Science, Vol. 44, pp. 254-64 (1954); and Annison et al., xe2x80x9cRuminal Ammonia Formation in Relation to the Protein Requirement of Sheepxe2x80x9d, Journal of Agricultural Science, Vol. 44, pp. 270-77 (1954). However, each of these documents does not disclose or suggest a method of decreasing nitrogen solubility of a ruminant feed material, according to one aspect of the present invention.
The related art discloses various possible protective agents for reducing the rumen degradation of protein feedstuffs. For example, formaldehyde, ethanol, wood molasses, lignin, acetic acid and the application of heat have been proposed as protective agents. However, use of such agents can have drawbacks. In this regard, formaldehyde is a known carcinogen to humans. Use of ethanol, acetic acid and the application of heat can be costly. In addition, lignin generally has a low nutritional value and can be unpalatable to livestock.
U.S. Pat. No. 5,709,894 (the ""894 patent) relates to a feed additive for ruminants. The feed additive comprises dried glutamic acid fermentation solubles, dried corn fermentation solubles or a mixture of dried glutamic acid fermentation solubles and dried corn fermentation solubles. See abstract at lines 1-4. The dried solubles have been dried to a total moisture content of less than 30% by weight at a temperature not less than 80xc2x0 F. and not more than 90xc2x0 F. See abstract at lines 4-7. The ""894 patent discloses that as a result of the drying, the nonprotein nitrogen fractions of the composition are reduced in their solubility so as to provide rumen bacteria with a sustained release source of ammonia nitrogen. The ""894 patent at col. 6, lines 16-21.
The ""894 patent relates to reducing the solubility of nonprotein nitrogen fractions. These nonprotein nitrogen fractions are present in the dried glutamic acid fermentation solubles, dried corn fermentation solubles or the mixture of dried glutamic acid fermentation solubles and dried corn fermentation solubles.
Swiss patent document No. 442,947 relates to a process for the production of monosodium glutamate. This document discloses that glutamic acid is produced by fermentation and it is converted into the monosodium salt. The salt is then isolated as a concentrated solution or as a component of a dry powder.
German patent document No. 1,222,773 relates to animal feeds or feed supplements containing a fermentation residue obtained from the production of glutamic acid by fermentation. The fermentation residue comprises solids filtered out of the fermentation medium and the mother liquor of the glutamic acid which has been crystalized and separated out.
In view of the foregoing, a need in the art exists for provision of a ruminant feed material comprising a protein feedstuff having an increased resistance to rumen degradation.
One object of the present invention is to provide a method of preparing a ruminant feed material having a decreased nitrogen solubility. Another object of the present invention is to provide a ruminant feed material having a decreased nitrogen solubility. The foregoing objectives are met by the present invention. According to one aspect, the present invention relates to a method of preparing a ruminant feed material with decreased nitrogen solubility, comprising mixing a liquid feed product containing a salt with a protein feedstuff. The protein feedstuff contains crude protein in an amount from 30% to 70% by weight. The liquid feed product containing a salt and the protein feedstuff are mixed under conditions sufficient to decrease the nitrogen solubility of the protein feedstuff.
According to a further aspect, the present invention provides a ruminant feed material with decreased nitrogen solubility, comprising a liquid feed product containing a salt contacted with a protein feedstuff. The protein feedstuff contains crude protein in an amount from 30% to 70% by weight. The protein feedstuff has a decreased nitrogen solubility in comparison with the uncontacted protein feedstuff.
According to one aspect, a liquid feed product is mixed with a protein feedstuff to reduce the rumen degradability of the protein feedstuff. That is, the protein feedstuff of the present invention does not comprise a component of the liquid feed product, but is mixed therewith. In contrast, the nonprotein nitrogen fractions disclosed in the ""894 patent discussed above, comprise a component of the fermentation solubles and are believed to not have value as bypass protein. The ""894 patent does disclose contacting a mixture of fermentation solubles with a wheat middlings carrier. The ""894 patent at col. 6, lines 60-64. However, it is believed that the wheat middlings carrier disclosed by the ""894 patent does not contain a sufficient amount of crude protein to provide a reduction in rumen degradability comparable to that achieved in the present invention. This aspect of the present invention is discussed in greater detail below.
Further, neither Swiss patent document No. 442,947 nor German patent document No. 1,222,773, each discussed above, relates to decreasing the rumen degradability of a protein feedstuff, as set forth in one aspect of the present invention.